Schaltmatten_Keypads

KEYPADS
Manufacturing Process
All of conductive rubber keypads and switches are compression-molded in precise carbon sreel tools using highly elastic,
non-toxic silicone rubber compounds.
After molding, all keypads are subjected to a two-hour post-curing cycle at a temperature of 200 o C. Post curing is essential to the
manufacturing process because it removes catalyst and oxidant residue retained by the keypad during the molding process,
stabilizes the physical properties of the silicone and increases thermal stability.
DIMENSIONAL TOLERANCE
Great care should be exercised when a keypad is designed using silicone rubber because it is a highly elastic material subject to
manufacturing variations. Tolerances for silicone rubber, by nature, need to be considerably larger than those for less-elastic
materials because silicone tolerances are affected by variances in shrink rates, molding conditions and material compounds.
Dimensional Tolerance*
Dimension
0.0 - 10.0 mm ± 0.10 mm
10.1 - 20.0 mm ± 0.15 mm
20.1 - 30.0 mm ± 0.20 mm
30.1 - 40.0 mm ± 0.25 mm
40.1 - 50.0 mm ± 0.30 mm
50.1 - 100.0 mm ± 0.35 mm
100.1 mm and up ± 0.5%
Angular dimension ±1 degree
* Contact us to determine if more precise tolerances
are available for your design.
ACTUATION FORCE TOLERANCES
The membrane shape and size of all rubber switches can be designed so that almost any actuation force and tactile feelcan be
realized. Most applications require positive tactile feel with relatively long life, so an actuation force of approximatly 125 - 150
grams is typically recommended with an accompanying snap ratio of approximately 40-60%.
Actuation Force Tolerances**
Design Force
50 g ± 15 g
75 g ± 20 g
100 g ± 25 g
125 g ± 30 g
150 g ± 35 g
175 g ± 40 g
200-250 g ± 50 g
250.1 g and up ± 30%
** Typical tolerance for actuation force is ± 25g. Optimum actuation force for best key performance is 80-150 g.
Conductive rubber switches can be successfully designed and manufactured with actuation forces ranging from a minimum of
20 g to a maximum of 500 g.
digital electronic gmbh Tel. +49 (0) 8221-708-0 Fax +49 (0) 8221 708-80
www.digitallehrer.de digital@digitallehrer.de
All specifications subject to change without notice.
4